What to use as infill

[williamglossop]

I'm planning on building a patio. The garden slopes and I'm considering building a low level retaining wall and then building up the ground level on one side of it to form a base for a patio. I'd plan on using 100 mm type 1 as the top layer (before flags etc). But what' the best way to bring the ground level up to this height? Ive got tons of rubble that i could use. Would this be suitable?

This pic is nicked if t'internet but is a similar idea.

 

[KenGMac]

williamglossop, Good evening.

Clean hard rubble will suffice as backfill.

One consideration I would advise is to install a drainage system behind the proposed wall.

using a suitable perforated pipe, led into a soakaway in the garden a set distance from the Property,

And a geotextile wrapped around a free draining rounded pebble area the geotextile should be taken up the rear face of the wall, and at the same time go under the perforated drain, the drain running at a very slight slope at the base of the wall. On the side away from the rear face of the wall the geotextile is brought up to ground level the space between the two geotextile layers is infilled with the rounded pebbles.

Reason for the drain and the pebbles Et All is to ensure that there is no water pressure build up behind the wall and reduce the appearance of dampness on the face of the wall coming through the wall.

 

[williamglossop]

Thanks Ken

Can't picture what you mean exactly re: drainage etc.

 

[KenGMac]

Have a look at this?

About as close as I can find tonight the DPC is optional, I would not bother because it is a slip plane allowing the wall to move forwards.

As for the Impermeable layer at the surface of the rear face of the wall ? a couple of layers of water proofing paint may assist?

Hope the sketch assists?

ken

 

[tomfe]

I don't think you'll need to add drainage under the patio, you are laying an impervious layer and the wall will not be very high.
I would however think about were all the water is going to go which hits the top, were is that going to drain to.